Conventionally, as a type of rice that cooks quickly, instant rice is known. The instant rice may be restored to edible rice by a quick simple preparation, and is useful as preserved food for emergencies. The instant rice is also useful as daily food.
Patent document 1 discloses a manufacturing method of instant rice which does not need a drainage treatment facility and which is capable of achieving a fine product appearance. This manufacturing method does not need a drainage treatment facility because hydration of raw material rice grains is performed by addition of a fixed amount of water instead of soaking in water in a soaking tank and there is no redundant water. Also, this manufacturing method gelatinizes the surface layer of rice grains in advance by a preparatory pressurized-steaming process to impart toughness. Accordingly, no crack is caused at the time of addition of the fixed amount of water, and the rice grains are not deformed in steps following the hydration step.
However, the instant rice obtained by the manufacturing method cannot be restored to edible rice simply by pouring hot water. To restore the instant rice to edible rice, it has to be boiled over a long time or has to be heated by microwave or the like.